Process for substantially gel-free polymerization of norbornene with dicyclopentadiene

ABSTRACT

A norbornene-type monomer is copolymerized with about 0% to about 95% by weight of dicyclopentadiene, based upon total polymer weight. The polymerization is conducted in the presence of (1) a catalyst comprising (a) at least one compound selected from the group consisting of dialkyl-aluminum iodides, alkylaluminum diodides and mixtures of trialkylaluminum compounds with iodine, (b) at least one dialkylaluminum chloride or alkylaluminum dichloride and (c) at least one monomer- or solvent-soluble tungsten compound, and (2) at least one nonconjugated acyclic olefin having at least one hydrogen on each double-bonded carbon atom. Catalyst components (a) and (b) are charged before catalyst component (c). Use of a catalyst containing components (a), (b) and (c) produces easy-processing and substantially gel-free polymers, whereas a catalyst containing only (a) and (c) or only (b) and (c) produces heavily gelled polymers.

BACKGROUND OF THE INVENTION

U.S. Pat. No. 3,597,403 teaches polymerization of certain unsaturated alicyclic compounds with a catalyst comprising (A) at least one compound selected from the group consisting of alkylaluminum dihalides, alkylaluminum sesquihalides and aluminum halides, (B) at least one compound selected from the group consisting of molecular oxygen, chlorine, bromine, iodine and cyanogenhalides, and (C) at least one transition metal compound selected from the group consisting of tungsten and molydenum carbonyl complex compounds. It is also known that certain hydrocarbon monoolefins may be used to adjust molecular weight of polyalkenamers (U.S. Pat. No. 3,816,382). The very broad teachings of the prior art fail to suggest a polymerization process for production of easy-processing and substantially gel-free norbornene-dicyclopentadiene copolymers. Such a process and copolymers are desired in order to simplify polymer removal from polymerization vessels.

SUMMARY OF THE INVENTION

A norbornene-type monomer is copolymerized with about 0% to about 95% by weight of dicyclopentadiene based upon total polymer weight. The polymerization is conducted in the presence of (1) a catalyst comprising (a) at least one compound selected from the group consisting of dialkylaluminum iodides, alkylaluminum diodides, and mixtures of trialkyl-aluminum compounds with elemental iodine, (b) at least one dialkylaluminum chloride or alkylaluminum dichloride and (c) at least one monomer- or solvent-soluble tungsten compound, and (2) at least one nonconjugated acyclic olefin having at least one hydrogen on each double-bonded carbon atom. Catalyst components (a) and (b) are charged before catalyst component (c).

DETAILED DESCRIPTION

A norbornene-type monomer is copolymerized with about 0% to about 95% by weight, more preferably from about 50% to about 95% by weight, and even more preferably from about 75% to about 95% by weight of dicyclopentadiene, based upon total polymer weight. The norbornene-type monomer has the formula ##STR1## wherein X is hydrogen or an alkyl group containing from 1 to 6 carbon atoms, more preferably from 1 to 3 carbon atoms. Examples of suitable norbornene-type monomers include 2-norbornene, 5-methyl-2-norbornene, 5-ethyl-2-norbornene, and the like. Excellent results were obtained with 2-norbornene and 5-methyl-2norbornene. The copolymers may also contain polymerized therein up to about 10% by weight of at least one other cycloolefin, based upon total polymer weight. Examples of suitable termonomeric cycloolefins include monocyclic monoolefins and diolefins containing from 4 to 12 carbon atoms, more preferably from 4 to 8 carbon atoms, such as cyclobutene, cyclopentadiene, cycloheptene, cyclooctene, 1,5-cyclooctadiene, cyclodecene and the like. Also suitable are bicyclic olefins containing from 7 to 16 carbon atoms and from 1 to 4 double bonds, more preferably from 8 to 12 carbon atoms and 2 or 3 double bonds, such as norbornadiene and the like. As would be obvious, cycloolefins which cannot be polymerized with ring-opening, e.g., cyclohexene and the derivatives thereof, are not employed as termonomers in the polymerization process of this invention.

The polymerization is conducted in the presence of (1) a catalyst comprising (a) at least one compound selected from the group consisting of dialkylaluminum iodides, alkylaluminum diiodides and mixtures of trialkylaluminum compounds with iodine, (b) at least one dialkylaluminum chloride or alkylaluminum dichloride and (c) at least one monomer- or solvent-soluble tungsten compound, and (2) at least one nonconjugated acyclic olefin having at least one hydrogen on each double-bonded carbon atom. Catalyst components (a) and (b) are charged before catalyst component (c).

Catalyst component (a) comprises at least one dialkyl-aluminum iodide or alkylaluminum diiodide wherein each alkyl group contains from 2 to 8 carbon atoms, more preferably from 2 to 4 carbon atoms, such as diethylaluminum iodide, ethyl-aluminum diiodide, propylaluminum diiodide, ethylpropyl-aluminum iodide and the like. A mixture of a trialkylaluminum compound and iodine may also be used wherein each alkyl group contains from 2 to 8 carbon atoms, more preferably from 2 to 4 carbon atoms, such as a mixture of triethylaluminum and iodine and the like. Excellent results were obtained with diethyl-aluminum iodide.

Catalyst component (b) comprises at least one dialkyl-aluminum chloride or alkylaluminum dichloride wherein each alkyl group contains from 2 to 8 carbon atoms, more preferably from 2 to 4 carbon atoms, such as diethylaluminum chloride, ethylaluminum dichloride, propylaluminum dichloride and the like. Catalyst component (a) is used in a molar ratio to catalyst component (b) from about 0.1/1 to about 10/1, more preferably from about 0.5/1 to about 2/1.

Catalyst component (c) comprises at least one monomer or solvent-soluble tungsten compound. Suitable tungsten compounds include tungsten carbonyl [W (CO)₆ ], tungsten oxytetrachloride, and the like. Also suitable and more preferred are tungsten halides, which include chlorides, bromides, iodides and fluorides such as tungsten hexachloride, tungsten hexafluoride and the like. Excellent results were obtained using tungsten hexachloride.

The combined amount of catalyst components (a) and (b) is from about 0.1 to about 10 millimoles per mole of monomer. The combined amount of catalyst components (a) and (b) is used in a catalytically effective molar ratio to tungsten compound from about 1 to about 80 moles per mole, more preferably from about 1 to about 50 moles per mole. The elemental iodine is used in the range of from about 0.25 mole to about 6 moles of elemental iodine per mole of trialkyl-aluminum compound, more preferably from about 0.5 to about 3 moles per mole. The catalyst components may be charged directly or in solution, but catalyst components (a) and (b) must be charged before the tungsten compound.

Surprisingly, the catalyst must contain at least one compound each of catalyst components (a), (b), and (c) in order to produce substantially gel-free norbornenedicyclopentadiene copolymers. For example, a mixture of diethylaluminum iodide, ethylaluminum dichloride and tungsten hexachloride was found to produce excellent results. In contrast, a catalyst containing only diethylaluminum iodide and tungsten hexachloride produced a heavily gelled polymer. Similarly, a catalyst containing only ethylaluminum dichloride and tungsten hexachloride produced a heavily gelled polyer. The utility of the three-part catalyst in the process of this invention was totally unexpected.

At least one nonconjugated acyclic olefin is used having at least one hydrogen on each double-bonded carbon atom and containing 2 to 12 carbon atoms, more preferably 2 to 8 carbon atoms. Inert substituents on the remaining carbon atoms are selected from the group consisting of hydrogens and alkyl groups containing 2 to 8 carbon atoms. Examples of suitable compounds include 1-olefins such as 1-butene, 3-methyl-1-butene, and the like; 2-olefins such as 2-pentene, 4-methyl-2-pentene and the like; 3-olefins such as 5-ethyl-3-octene and the like; nonconjugated diolefins such as 1,6-hexadiene and the like; nonconjugated triolefins such as 1,4,7-octatriene and the like; and like compounds. More preferably the nonconjugated acyclic olefin is selected from the group consisting of 1-olefins and 2-olefins containing 2to 8-carbon atoms such as 1-butene, 3-methyl-1-butene, 2-pentene, 4-methyl-2-pentene and the like. Compounds not having hydrogen atoms substituted on double-bonded carbons are unreactive in this invention, and conjugated olefins such as butadiene, isoprene and the like are active inhibitors.

The nonconjugated acyclic olefin is used in a molar ratio to total norbornene and dicyclopentadiene from about 0.0001 to about 0.3 mole per mole. The nonconjugated acyclic olefin may be charged directly or in solution at any point in the charge procedure, but it is more preferably charged along with the monomers. When charged last, the nonconjugated acyclic olefin preferably is charged before reaction begins.

Use of a polymerization solvent in the process of this invention is preferred but not required. Suitable solvents include aliphatic or cycloaliphatic hydrocarbon solvents containing 4 to 10 carbon atoms such as pentane, hexane, heptane, octane, cyclohexane, cyclooctane and the like; aromatic hydrocarbon solvents containing 6 to 14 carbon atoms and which are liquid or easily liquified such as benzene, toluene, naphthalene and the like; and substituted hydrocarbons wherein the substituents are inert, such as dichloromethane, chloroform, chlorobenzene and the like. Benzene was found to be an excellent solvent. The solvent may be added at any point in the charging procedure, but a portion is more preferably used to dissolve the catalyst and the remainder added before the catalyst solution.

A polymerization activator may be used but is not generally needed. Examples of activators include water, methanol, ethanol, isopropyl alcohol, benzyl alcohol, phenol, ethyl mercaptan, 2-chloroethanol, 1,3-dichloropropanol, p-bromophenol, epichlorohydrin, ethylene oxide, cyclopentene-2-hydroperoxide, cumyl hydroperoxide, tertiary butyl peroxide, benzoyl peroxide, and air or oxygen. Excellent activation is obtained by using air or a peroxide or hydroperoxide as the activator, especially by using the organic peroxides such as benzoyl peroxide. The activator may be employed in a range from about 0 moles to about 3 moles per mole or organoaluminum compound, more preferably from about 0 to about 1 mole per mole. The activator may be added at any point in the charge procedure, but it is more preferably added last, after the tungsten compound.

The monomers may be added at any point in the charging procedure. Normally, the monomers, solvent and nonconjugated acyclic olefin are added first to the reactor vessel. The ingredients may be added separately or as a mixture of ingredients. Catalyst component (a) (alkylaluminum iodide compound or mixture of trialkylaluminum compound and elemental iodine) and catalyst component (b) (alkylaluminum chloride compound) are added next as a mixture or separately in either order, but usually in solution in a solvent described heretofore. More preferably catalyst component (a) is added first in order to carry out the titration procedure described below, followed by catalyst component (b). The tungsten compound is added next as a solution in a solvent described heretofore, followed by the activator if used. The tungsten compound must be added after catalyst components (a) and (b).

Monomeric impurities such as water and the like should be removed prior to addition of the tungsten compound. The alkylaluminum iodide compound or mixture of trialkylaluminum compound and elemental iodine may be used to titrate the monomers or mixture of monomers and solvent until a color change from pink to colorless or slightly yellow is noted. A catalytically effective amount of alkylaluminum iodide compound or a mixture of trialkylaluminum compound and elemental iodine may then be added, followed by addition of catalyst component (b) and finally the tungsten compound. The end point of the titration is typically difficult to pinpoint exactly. With minor impurities present, up to ten times the catalytically effective amount and more of the alkylaluminum iodide or mixture of trialkylaluminum compound and iodine may be required to render the impurities harmless.

Both the mixing of catalyst components and the reaction are preferably carried out in an inert atmosphere such as nitrogen and in the substantial absence of air or water. The reaction is conducted under sufficient pressure to keep the monomers in liquid state, the pressure required depending upon the reaction temperature. The particular solvent system selected must be liquid under the reaction conditions used. Reaction temperature may be from about -50° C to about 100° C, more preferably from about 0° C to about 35° C. The polymerization may be short-stopped by addition of alcohols, amines or carboxylic acids such as ethanol, t-butyl phenol, diethylamine, acetic acid and the like.

The polymer may be isolated by any method known to the art such as by direct drying under reduced pressure, by precipitation using an alcohol such as methanol, ethanol, isopropanol and the like, or by steam or hot water stripping. The polymer is recovered and may be washed further with water or an alcohol and then dried.

The copolymers of this invention are high molecular weight products having an inherent viscosity from about 0.1 to about 10, more generally from about 0.5 to 5 and are greater than 90% soluble in a solvent defined heretofore. Substantial insolubility indicates the presence of gel. By inherent viscosity (η_(inh)) is meant a value obtained by dividing the natural logarithm of relative viscosity (η_(r) = ratio of solution viscosity to solvent viscosity) by the concentration (c) being measured in grams of polymer per 100 milliliters of solvent at a given temperature, in this case 0.1 gram in 100 milliliters of toluene at 25° C: ##EQU1## The inherent viscosity is regarded as a measure of molecular weight and is reported in units of deciliters/gram.

The following examples illustrate the present invention more fully.

EXAMPLES 1 - 10

2-Norbornene was copolymerized with dicyclopentadiene by the following procedure. Glass or glass-lined reactor vessels were used. Each vessel was well-cleaned with soap and water, rinsed with acetone, heated in an oven at 140° C and thereafter flushed with nitrogen. 2-Norbornene and dicyclopentadiene were mixed with benzene and charged to the reactor vessel. 1-Butene was added as a 2 volume percent solution in benzene. The diethylaluminum iodide (0.5 molar solution in benzene) was charged next, followed by ethylaluminum dichloride (0.25 molar solution in benzene). Tungsten hexachloride (0.05 molar solution in benzene) was added last. The polymerizations were performed at about 22° C and produced little heat. Little agitation was required from efficient polymerization. The reactions were short-stopped by the addition of ethanol, and the polymers were precipitated and washed using ethanol. About 1 wt.% of di-t-butyl paracresol was added to the polymer as an antioxidant, and the polymer was dried in a vacuum oven at about 50° C. Percent yield was based upon the total weight of norbornene, dicyclopentadiene and 1-butene charged. The grams and moles of reactants, yields, percentages of dicyclopentadiene in polymers, inherent viscosities (IV) and % insolubilities of the polymers are set forth in Table I.

                                      TABLE I                                      __________________________________________________________________________     EXAMPLES            1    2    3    4    5                                      __________________________________________________________________________     Benzene, grams      71.3 72.7 74.3 75.9 84.5                                   moles               0.91 0.93 0.95 0.97 1.08                                   2-Norbornene, grams 0.82 0.82 0.8  0.82 0.88                                   millimoles          8.7  8.7  8.4  8.7  9.3                                    DCPD, grams         8.75 8.7  8.6  9.3  9.3                                    millimoles          66   66   65   70   70                                     1-Butene, grams     0.19 0.19 0.19 0.19 0.02                                   millimoles          3.3  3.3  3.3  3.3  0.4                                    Et.sub.2 AlI, grams 0.016                                                                               0.016                                                                               0.016                                                                               0.016                                                                               0.010                                  millimoles          0.075                                                                               0.075                                                                               0.075                                                                               0.075                                                                               0.05                                   EtAlCl.sub.2, grams 0.010                                                                               0.010                                                                               0.019                                                                               0.038                                                                               0.012                                  millimoles          0.075                                                                               0.075                                                                               0.15 0.3  0.1                                    WCl.sub.6, grams    0.006                                                                               0.006                                                                               0.008                                                                               0.008                                                                               0.001                                  millimoles          0.015                                                                               0.015                                                                               0.02 0.02 0.0025                                 Et.sub.2 AlI/EtAlCl.sub.2 molar ratio                                                              1.0  1.0  0.5  0.25 0.5                                    Millimoles Al compound/mole monomer                                                                1.9  1.9  2.9  4.5  1.9                                    Al/W molar ratio    10.0 10.0 11.2 18.7 44                                     Time, Hours         1.0  17.0 17.0 17.0 16.0                                   Polymer yield, grams                                                                               9.2  8.3  9.1  8.5  6.6                                    Wt.%                94   85   94   82   6.4                                    Wt.% DCPD in polymer                                                                               90   90   90   90   91                                     IV                  0.48 0.47 0.53 0.47 2.3                                    Appearance          Smooth                                                                              Smooth                                                                              Smooth                                                                              Smooth                                                                              Smooth                                 __________________________________________________________________________     EXAMPLES            6    7    8    9    10                                     __________________________________________________________________________     Benzene, grams      82.1 74.0 75.5 73.8 72.0                                   moles               1.05 0.95 0.97 0.94 0.92                                   2-Norbornene, grams 0.85 0.8  0.82 0.85 0.85                                   millimoles          9.0  8.5  8.7  9.0  9.0                                    DCPD, grams         8.65 8.62 8.6  8.7  8.7                                    millimoles          65   65   65   66   66                                     1-Butene, grams     0.05 0.10 0.02 0.05 0.10                                   millimoles          0.9  1.8  0.4  0.9  1.8                                    Et.sub.2 AlI, grams 0.021                                                                               0.016                                                                               0    0    0                                      millimoles          0.1  0.075                                                                               0    0    0                                      EtAlCl.sub.2, grams 0    0    0.016                                                                               0.016                                                                               0.016                                  millimoles          0    0    0.125                                                                               0.125                                                                               0.125                                  WCl.sub.6, grams    0.003                                                                               0.003                                                                               0.001                                                                               0.001                                                                               0.001                                  millimoles          0.0075                                                                              0.0075                                                                              0.0025                                                                              0.0025                                                                              0.0025                                 Et.sub.2 AlI/EtAlCl.sub.2 molar ratio                                                              --   --   --   --   --                                     Millimoles Al compound/mole monomer                                                                1.3  1.0  1.7  1.6  1.6                                    Time, Hours         16   16   16   16   16                                     Polymer yield, grams                                                                               1.2  5.6  10.6 1.6  5.1                                    Wt.%                13   59   100  17   53                                     Wt.% DCPD in polymer                                                                               90   90   91   91   90                                     IV                  1.50 0.26 2.31 0.78 0.51                                   Appearance          Gelled                                                                              Gelled                                                                              Gelled                                                                              Gelled                                                                              Gelled                                 __________________________________________________________________________     Symbols in Table I:                                                            DCPD =  Dicyclopentadiene                                                      Et.sub.2 AlI = Diethylaluminum iodide                                          EtAlCl.sub.2 = Ethylaluminum dichloride                                        WCl.sub.6 = Tungsten hexachloride                                               ##STR2##                                                                       ##STR3##                                                                      Examples 1 through 5 illustrate production of a clear, smooth, gel-free        norbornene-dicyclopentadiene copolymer cement in good yield with proper        reactants and conditions as described heretofore; 1-butene,                    diethylaluminum iodide, ethylaluminum dichloride, and tungsten                 hexachloride were used with suitable Al/monomer and Al/W ratios, and the       aluminum compounds were charged before the tungsten hexachloride. In           contrast, examples 6 and 7 illustrate production of gelled, grainy             polymer using a catalyst without the necessary second component,               ethylaluminum dichloride. Examples 8, 9 and 10 illustrate production of        gelled, grainy polymer using a catalyst without the necessary first       

5-Methyl-2-norbornene was copolymerized with dicyclopentadiene using the same procedure described for examples 1 - 5. The grams and moles of reactants, yields, percentages of DCPD in polymers, inherent viscosities (IV) and % insolubilities of the polymers are set forth in Table II.

                                      TABLE II                                     __________________________________________________________________________     EXAMPLES            11   12   13   14   15                                     __________________________________________________________________________     Benzene, grams      69.2 69.6 75.1 70.4 417                                    moles               0.89 0.89 0.96 0.90 5.34                                   5-Methyl-2-norbornene, grams                                                                       7.7  6.0  7.6  6.0  25.3                                   millimoles          71   55   70   55   234                                    DCPD, grams         1.1  2.8  1.1  2.9  29.0                                   millimoles          8    21   8    22   219                                    1-Butene, grams     0.09 0.09 0.14 0.14 1.0                                    millimoles          1.6  1.6  2.5  2.5  18                                     Et.sub.2 AlI, grams 0.010                                                                               0.010                                                                               0.005                                                                               0.005                                                                               0.053                                  millimoles          0.05 0.05 0.025                                                                               0.025                                                                               0.25                                   EtAlCl.sub.2, grams 0.006                                                                               0.006                                                                               0.010                                                                               0.010                                                                               0.032                                  millimoles          0.05 0.05 0.075                                                                               0.075                                                                               0.25                                   WCl.sub.6, grams    0.006                                                                               0.006                                                                               0.006                                                                               0.006                                                                               0.040                                  millimoles          0.015                                                                               0.015                                                                               0.015                                                                               0.015                                                                               0.10                                   Et.sub.2 AlI/EtAlCl.sub.2 molar ratio                                                              1.0  1.0  0.3  0.3  1.0                                    Millimoles Al compound/mole monomer                                                                1.2  1.3  1.2  1.3  1.1                                    Al/W molar ratio    6.7  6.7  6.7  6.7  5.0                                    Time, Hours         1.4  1.4  1.3  0.3  1.4                                    Polymer yield, grams                                                                               8.8  9.0  8.9  8.9  60.4                                   Wt.%                99   100  100  100  100                                    Wt. % DCPD in polymer                                                                              12   31   12   32   52                                     IV                  2.11 2.43 1.51 1.57 1.07                                   Appearance          Smooth                                                                              Smooth                                                                              Smooth                                                                              Smooth                                                                              Smooth                                 __________________________________________________________________________     EXAMPLES            16   17   18   19   20                                     __________________________________________________________________________     Benzene, grams      424  414  2115 417  413                                    moles               5.42 5.30 27.08                                                                               5.34 5.29                                   5-Methyl-2-norbornene, grams                                                                       37.0 15.0 198.6                                                                               37.1 41.3                                   millimoles          342  139  1836 343  382                                    DCPD, grams         16.5 40.2 60   11.9 12.0                                   millimoles          125  304  454  90   91                                     1-Butene, grams     1.0  1.0  2.5  0.007                                                                               0.007                                  millimoles          18   18   45   0.1  0.1                                    Et.sub.2 AlI, grams 0.053                                                                               0.053                                                                               0.265                                                                               0.053                                                                               0.026                                  millimoles          0.25 0.25 1.25 0.25 0.125                                  EtAlCl.sub.2, grams 0.032                                                                               0.032                                                                               0.159                                                                               0.016                                                                               0.024                                  millimoles          0.25 0.25 1.25 0.125                                                                               0.187                                  WCl.sub.6, grams    0.040                                                                               0.030                                                                               0.198                                                                               0.020                                                                               0.030                                  millimoles          0.10 0.075                                                                               0.5  0.05 0.075                                  Et.sub.2 AlI/EtAlCl.sub.2 molar ratio                                                              1.0  1.0  1.0  2.0  0.7                                    Millimoles Al compound/mole monomer                                                                1.1  1.1  1.1  0.9  0.6                                    Al/W molar ratio    5.0  6.7  2.5  7.5  4.1                                    Time, Hours         1.5  1.3  0.25 0.1  1.3                                    Polymer, yield, grams                                                                              50.6 39.5 252  48.3 52.3                                   Wt.%                93   70   --   99   98                                     Wt.% DCPD in Polymer                                                                               30   71   23   24   23                                     IV                  1.68 --   2.50 4.13 3.89                                   Appearance          Smooth                                                                              Smooth                                                                              Smooth                                                                              Smooth                                                                              Smooth                                 __________________________________________________________________________     EXAMPLES            21   22   23   24   25                                     __________________________________________________________________________     Benzene, grams      416  402   410 413  420                                    moles               5.33 5.15 5.25 5.29 5.38                                   5-Methyl-2-norbornene, grams                                                                       41.3 41.3 41.4 41.7 43.3                                   millimoles          382  382  383  385  400                                    DCPD, grams         12.8 11.9 13.0 12.5 11.9                                   millimoles          97   90   98   95   90                                     1-Butene, grams     0.007                                                                               0.014                                                                               0.133                                                                               0.133                                                                               0.178                                  millimoles          0.1  0.2  2.3  2.3  3.1                                    Et.sub.2 AlI, grams 0.026                                                                               0.026                                                                               0.026                                                                               0.026                                                                               0.026                                  millimoles          0.125                                                                               0.125                                                                               0.125                                                                               0.125                                                                               0.125                                  EtAlCl.sub.2, grams 0.032                                                                               0.032                                                                               0.032                                                                               0.032                                                                               0.064                                  millimoles          0.25 0.25 0.25 0.25 0.5                                    WCl.sub.6, grams    0.020                                                                               0.020                                                                               0.020                                                                               0.020                                                                               0.028                                  millimoles          0.05 0.05 0.05 0.05 0.07                                   Et.sub.2 AlI/EtAlCl.sub.2 molar ratio                                                              0.5  0.5  0.5  0.5  0.25                                   Millimoles Al compound/mole monomer                                                                0.8  0.8  0.8  0.8  1.2                                    Al/W molar ratio    7.5  7.5  7.5  7.5  8.9                                    Time, Hours         1.0  0.03 0.5  0.4  0.8                                    Polymer yield, grams                                                                               51.8 46.9 47.1 48.8 41.6                                   Wt.%                96   88   86   90   75                                     Wt.% DCPD in polymer                                                                               24   24   22   23   22                                     IV                  4.33 3.97 2.07 1.43 1.43                                   Appearance          Smooth                                                                              Smooth                                                                              Smooth                                                                              Smooth                                                                               Smooth                                __________________________________________________________________________     Symbols in Table II:                                                           DCPD = Dicyclopentadiene                                                       Et.sub.2 AlI = Diethylaluminum iodide                                          EtAlCl.sub.2 = Ethylaluminum dichloride                                        WCl.sub.6 = Tungsten hexachloride                                               ##STR4##                                                                       ##STR5##                                                                 

Copolymers of varying amounts of dicyclopentadiene with norbornene (Example 26) and 5-methyl-2norbornene (Examples 27-33) were prepared following the general catalyst preparation and addition procedure of this invention as demonstrated by Example 1. The copolymers were admixed with compounding ingredients according to the recipes in Table III (all amounts are in parts by weight) and cured. Compounding was done using a two-roll mill operating at a roll temperature of about 40° C to about 90° C.

Physical testing of the copolymers was performed, and the results are set forth in Table IV. 100% modulus, tensile strength and ultimate elongation were determined according to ASTM D412-68 using Die D dumbbells. Compression fatigue (ΔT, ° F) was tested according to ASTM D623-67 at 212° F using a Goodrich flexometer with a 0.175 inch stroke, 55 lb. static load (143 lb/in.²), 20 minute conditioning time and 25 minute running time. Durometer hardness was measured according to D2240-68 using a Shore Type A durometer and a one second indentation hardness time interval. Pico abrasion resistance was measured according to ASTM D2228-69 using a 4.5 kg weight, a 60 rpm speed and 240 revolutions. Abrasion index was calculated according to section 11.3 of the latter procedure.

The physical testing data indicates that the polymers tested have a good balance of physical properties that make them suitable for tire rubber applications. The outstanding property is high tensile strength at high temperatures and is particularly important in truck tire rubbers, since truck tires run "hotter" under a heavier load than other tires.

                                      TABLE III                                    __________________________________________________________________________     EXAMPLES            26  27  28  29  30  31  32  33                             __________________________________________________________________________     Copolymer           100 100 100 100 100 100 100 100                            Carbon Black, HAF, N330                                                                            95  95  70  130 112 110 110 85                             Paraffinic Oil      75  75  40  125 100 100 100 62                             Stearic Acid        5   5   5   5   5   5   5   5                              Zinc Oxide          5   5   5   5   5   5   5   5                              Sulfur              4   3   1.5 4   3.5 4   4   4                              N-cyclohexyl-2-benzothiazole sulfenamide                                                           4   3   1.5 4   3.5 4   4   4                              Antioxidant         1   1   1   1   1   1   1   1                              __________________________________________________________________________

                                      TABLE IV                                     __________________________________________________________________________     EXAMPLES          26   27   28   29   30   31   32   33                        __________________________________________________________________________     Wt.% Dicyclopentadiene                                                                           0    22   22   23   24   32   53   53                        IV                3.60 3.89 4.03 4.33 4.13 2.39 2.47 1.07                      Cure Time at 160°, minutes                                                                10   7    8    7    6    8    8    30                        100% Modulus at 25° C, psig                                                               825  1000 1080 920  640  600  1000 2080                      100% Modulus at 100° C, psig                                                              640  480  260  580  440  260  480  600                       Tensile at 25° C, psig                                                                    3180 3000 3000 1920 2200 2320 2680 2800                      Tensile at 100° C, psig                                                                   1360 1600 2000 1200 1200 1090 1080 1200                      % Ultimate Elongation at 25° C                                                            235  215  250  165  210  220  195  135                       % Ultimate Elongation at 100° C                                                           165  245  405  165  210  290  190  170                       Compression Fatigue (ΔT, ° F)                                                       72   61   59   42   58   55   51   50                        Durometer Hardness                                                                               74   72   78   72   75   79   81   88                        Low Temperature Stiffening, T.sub.2, ° C                                                  -16  -23  -10  -23  -25  - 8  2    8                         Pico Abrasion Index                                                                              --   158  --   --   --   --   --   85                        __________________________________________________________________________

The norbornene-dicyclopentadiene copolymers are plastics but are also compatible with high levels of oil (up to 400 parts by weight oil and more, more preferably 100 parts by weight oil, per 100 parts by weight polymer). The oil extended polymers may be vulcanized to produce elastomeric compositions. Vulcanized and oil-loaded norbornene-dicyclopentadiene copolymers containing increasing amounts of dicyclopentadiene have increasingly better green strength and higher tensile strength (at room temperature and 100° C), and the compositions are suitable for use in tires, particularly in truck tires, as well as in other rubber goods. Suitable vulcanizing agents such as elemental sulfur or a thiuram di- or polysulfide and a broad range of accelerators and other compounding ingredients known to the art may be used together with the polymers produced by the process of this invention. 

I claim :
 1. A process comprising polymerization of a norbornene-type monomer with about 0% to about 95% by weight of dicyclopentadiene, based upon total polymer weight, said norbornene-type monomer having the formula ##STR6## where X is hydrogen or an alkyl group containing from 1 to 6 carbon atoms, said polymerization being conducted in the presence of
 1. catalyst comprising (a) at least one compound selected from the group consisting of dialkylaluminum iodides, alkylaluminum diiodides and mixtures of trialkylaluminum compounds with elemental iodine wherein each alkyl group contains from 2 to 8 carbon atoms, (b) at least one dialkylaluminum chloride or alkylaluminum dichloride wherein each alkyl group contains from 2 to 8 carbon atoms and (c) at least one tungsten compound soluble in the monomer mixture or in a solvent selected from the group consisting of aliphatic and cycloaliphatic hydrocarbon solvents containing 4 to 10 carbon atoms and liquid or easily liquified aromatic hydrocarbon solvents containing 6 to 14 carbon atoms, wherein the molar ratio of said (a) to said (b) is from about 0.1/1 to about 10/1, the catalytically effective amount of the combined total of said (a) and (b) is from about 0.25 to about 10 millimoles per mole of monomer, said (a) and (b) are charged before said (c), the molar ratio of the combined total of (a) and (b) to (c) is from about 1/1 to about 80/1 moles per mole, and the molar ratio of said elemental iodine to said trialkylaluminum compound is from about 0.25/1 to about 6/1 moles per mole, and2. at least one nonconjugated acyclic olefin containing from 2 to 12 carbon atoms and having at least one hydrogen on each double-bonded carbon atoms, said acyclic olefin being used in a molar ratio to monomer from about 0.0001/1 to about 0.3/1 mole per mole.
 2. A process of claim 1 wherein X is hydrogen or an alkyl group containing from 1 to 3 carbon atoms, said tungsten compound is a tungsten halide, the molar ratio of the combined total of (a) and (b) to (c) is from about 1/1 to about 50/1 moles per mole, the molar ratio of elemental iodine to trialkylaluminum compound is from about 0.5/1 to about 3/1 moles per mole, and said nonconjugated acyclic olefin is a 1-olefin or 2-olefin containing from 2 to 8 carbon atoms.
 3. A process of claim 2 wherein said norbornene-type monomer is 2-norbornene.
 4. A process of claim 3 wherein the catalyst comprises (a) at least one compound selected from the group consisting of diethylaluminum iodide, ethylaluminum diiodide, and a mixture of triethylaluminum and elemental iodine, (b) diethylaluminum chloride, ethylaluminum dichloride or a mixture thereof and (c) tungsten hexachloride.
 5. A process of claim 4 wherein the catalyst comprises (a) ethylaluminum dichloride, (b) diethylaluminum iodide, and (c) tungsten hexachloride.
 6. A process of claim 2 wherein said norbornene-type monomer is 5-methyl-2-norbornene.
 7. A process of claim 6 wherein the catalyst comprises (a) at least one compound selected from the group consisting of diethylaluminum iodide, ethylaluminum diiodide, and a mixture of triethylaluminum and elemental iodine, (b) diethylaluminum chloride, ethylaluminum dichloride or a mixture thereof and (c) tungsten hexachloride.
 8. A process of claim 7 wherein the catalyst comprises (a) ethylaluminum dichloride, (b) diethylaluminum iodide, and (c) tungsten hexachloride. 